<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        a{
            background-color: green;
            color: white;
            width: 139px;
            height: 60px;
            display: inline-block;
            text-decoration: none;
            text-align: center;
            line-height: 50px;
        }
        .a1{
            background-image: url(./daohang1.png);
        }
        .a1:hover{
            background-image: url(./daohang2.png);
        }
        .a2{
            background-image: url(./daohang2.png);
        }
        .a2:hover{
            background-image: url(./daohang3.png);
        }
        .a3{
            background-image: url(./daohang3.png);
        }
        .a3:hover{
            background-image: url(./daohang4.png);
        }
        .a4{
            background-image: url(./daohang4.png);
        }
        .a4:hover{
            background-image: url(./daohang1.png);
        }
    </style>
</head>
<body>
    <a href="#" class="a1">五彩导航</a>
    <a href="#" class="a2">五彩导航</a>
    <a href="#" class="a3">五彩导航</a>
    <a href="#" class="a4">五彩导航</a>

    <div>连接的挺好</div>
</body>
</html>